Regulation 17 Sampling at treatment works
Subject to paragraphs (2) to (4), in each year a water undertaker shall take from the point at which water leaves each treatment works which serves its water supply zones for analysis for testing for compliance with the parameters mentioned in Table 7 not less than the standard number of samples.
Where in each of three successive years the result of the analysis of the samples taken in accordance with paragraph (1) has established an absence of faecal and total coliforms and no significant increase in colony counts, the number of samples to be taken in the next following year from the point at which water leaves that works in respect of those parameters or that parameter, as the case may be, may, subject to paragraph (5), be the reduced number:
Provided that this paragraph shall not apply where the following year is 1990 and shall apply where the following year is 1991 or 1992 with the modifications specified in paragraph (3) below.
Paragraph (2) shall apply–
where the following year is 1991 as if it referred to 1990 instead of three successive years;
where the following year is 1992 as if it referred to two years instead of three years.
The number of samples to be taken in 1990 in respect of any parameter mentioned in Table 7 may, if on the application of the water undertaker the Secretary of State so authorises, be the reduced number.
A reduced number of samples may be taken in accordance with paragraph (2) in respect of works supplying for domestic purposes an average volume of more than 2,000 m3/d of water only if the water undertaker is of the opinion that there is no foreseeable risk that faecal or total coliforms will be present in the supply or the works are so designed that a failure of the disinfection process will bring about automatically a cessation of the supply.